Koala Virus Explaining Accumulated ‘Junk’ DNA In The Human Genome

The cuddly koala bear could help us explain our very own genome.
CREDIT-Chris Fithall

Junk DNA has always been the topic of interest for all the bioscientist worldwide. A new research led by the international team of researchers found that koala virus could help to describe the millions of years of accumulated junk DNA in the human genome.

The research team is exploring the virus which infected koala to know how virus modifies DNA of human and other species.

During their study, the team of scientist studied the effect of the retrovirus. Retrovirus is the RNA virus having single strand which enters into a host cell to produce DNA using its RNA genome. Some of these are so parasitic in nature that they infect germline also which in turn can lead to mutation in the genome of their all future offsprings.

In human, retrovirus insertion began a million years ago so it was quite difficult to explore the interaction between the human genome and virus.

But through previous studies, a great news came for the scientist but not for the koala. A koala virus could help researchers explain millions of years of accumulated junk DNA in the human genome.

An international team of researchers – including scientists from The University of Queensland – is studying a virus infecting koalas in the hope it could demonstrate how viruses have altered the DNA of humans and other species throughout history.

Virologist Professor Paul Young, the Head of UQ’s School of Chemistry and Molecular Biosciences, said the team has analyzed the effects of the retrovirus infection.

“Retroviruses insert their genome into their host’s chromosome, from where they make more copies of themselves, Some can also infect what is known as germline cells, which alters the host genetic code and that of all their descendants,” added Professor Paul.

Retrovirus insertions in humans date back more than five million years, which means it’s difficult to know what happened when the first interactions took place.

“About a decade ago, we discovered that the wild koala population was being invaded by a retrovirus,” Professor Young said.

This news was like an opportunity to study the association between the host and retrovirus genome from the beginning.

These research led to the finding that these new retroviruses have the ability to multiply continuously within a species which can also lead to disastrous consequences. But what they also observed that with time the effects of retrovirus usually stopped and either took on new functions or became inert junk DNA.

“Until now, scientists could only guess at why and how this happened,” Professor Young said.

UQ’s Professor Joanne Meers said it would be exciting to see a retrovirus in action. “Because the koala retrovirus is still relatively young – less than 50,000 years old – and not yet ‘fixed’ in a certain location within the koala genome, scientists can monitor this early engagement between a retrovirus and its host.”

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